Pasteurization tunnels are known to be used for pasteurizing filled products, where the filled containers, for example bottles, cans or other beverage packs, are transported on a conveyor belt through the pasteurization tunnel and simultaneously treated from above by being sprayed with a heated liquid, in particular hot water. In order to increase machine performance, it is furthermore known to arrange several similar treatment decks of the pasteurization tunnel one upon the other to divide the product stream in parallel into several partial product streams which are essentially treated equally.
In a preferred variant of known pasteurization tunnels, the products to be pasteurized are sprayed from above by means of spraying pipes arranged transversely to the direction of transport of the products. The spraying pipes are each closed at one end and are connected at the other end to a common supply conduit for the spraying liquid. The spraying pipes are thus each connected in parallel as regards the flow of spraying liquid. With such a multi-level parallel connection of the treatment decks, uniform treatment conditions over all treatment decks can be obtained.
However, one problem is that at the end of the respective spraying pipes, in the last runnings of the flow behind the nozzle that was in each case the last one to be reached by the flow, deposits accumulate which can narrow or even clog individual spraying nozzles of the spraying pipes, so that the pouring amount discharged from the respective spraying pipe cannot be kept uniform for all spraying pipes and treatment decks. Therefore, such deposits must be regularly removed through access openings at the end of the spraying pipes. A further problem here is that a plurality of such access openings must be provided which are sometimes difficult to access due to the multi-level construction of such pasteurization tunnels. Due to their construction, all treatment decks are in this respect essentially equally susceptible to trouble. The inspection of spraying during operation is correspondingly intricate.
Therefore, there is a demand for pasteurization tunnels and corresponding pasteurization methods where the fault frequency due to deposits in the spraying pipes, and thus the efforts for the inspection and cleaning of individual spraying pipes, can be reduced.